Your hens lay eggs through their cloaca, or what we call the vent. While eggs exit through the same vent used for everything a chicken excretes, the tissue of the uterus extends with the egg (a sort of inside-out trick) until the egg is entirely out of the vent.

Where do the eggs come out of a chicken?

When the process is complete, the shell gland at the bottom end of the oviduct pushes the egg into the cloaca, a chamber just inside the vent where the reproductive and excretory tracts meet — which means, yes, a chicken lays eggs and poops out of the same opening.

How are eggs laid?

The laying process starts when light entering the hen's eye activates a photosensitive gland (the pineal gland) positioned nearby. Once stimulated, this gland triggers a process that leads to the release of an egg, or oocyte, from the hen's ovary. ... The orifice through which the egg leaves the hen is called the vent.